It is well documented that solar energy can be an effective means of cleaning contaminated water. This is because ultraviolet (UV) light destroys the formation of DNA linkages in microorganisms, thereby preventing them from reproducing and thus rendering them harmless.

Fuel cells are used to produce electricity. They are considered a promising technology to replace conventional combustion engines in vehicles. Fuel cells may also replace batteries in portable electronic equipment. The most widely used types of fuel cells for mobile devices are Proton Exchange Membrane fuel cells (PEM FC) which are often used in vehicles, and Direct Methanol fuel cells, used in portable applications. PEM fuel cells use hydrogen or certain alcohols such as methanol as fuel.

Under the anaerobic (oxygen free) conditions of landfill sites, organic waste is broken down by micro-organisms, leading to the formation of landfill gas (LFG). LFG is a gaseous mixture which consists mostly of methane and carbon dioxide, but also of a small amount of hydrogen and occasionally trace levels of hydrogen sulphide.

Hybrid technology systems combine two or more technologies with the aim to achieve efficient systems. Possible combinations are: wind-solar photovoltaic (PV) hybrid systems, wind-diesel hybrid systems, fuel cell-gas turbine hybrid systems, wind-fuel cell hybrid systems, etc. (see the short descriptions below). Hybrid systems combine numerous electricity production and storage units to meet the energy demands of a given facility or community (Solar Energy Technologies Program, 2006).